The present invention relates to a child-proof screwcap closure having
A. AN INNER CAP WHICH CAN BE SCREWED ONTO THE DISPENSING ORIFICE OF A CONTAINER,
B. AN OUTER CAP WHICH COVERS THE SAID INNER CAP AND, IN THE NON-ACTUATION POSITION, IS ROTATABLY CARRIED THEREON WITHOUT CAUSING IT TO EXECUTE THE SAME MOVEMENT,
C. A COUPLING MEMBER WHICH, WHEN THE CLOSURE IS ACTUATED TO OPEN IT, PRODUCES A POSITIVE ENGAGEMENT BETWEEN THE INNER CAP AND THE OUTER CAP AND
D. A SEALING MEMBER WHICH CAN BE MOUNTED BETWEEN THE ORIFICE RIM OF THE CONTAINER AND THE INNER WALL OF THE INNER CAP.
In recent years there have been many attempts to invent a child-proof screw closure, which can only be opened if certain manipulations are executed with the cap which acts as the closure of a container containing tablets or the like, for example a small bottle or box. Most of these known devices comprise the four abovementioned components. The third component is frequently a spring-type member, which presents the hazard of fatigue phenomena, or even of breaking off. Since it is in most cases necessary to manufacture this component from metal or from a plastic, for which latter case the only suitable method of manufacture is, in general, a modern injection molding process, a difficulty which readily presents itself is to find suitable molds and cores which will not be so highly complicated as to make the process too expensive.
Accordingly, it is an object of the present invention to provide a child-proof screw-cap closure which can be manufactured simply, without complicated molds and cores, by injection-molding of a plastic, and which also does not present a risk of fatigue or breaking-off.
According to the invention, this object is achieved by a child-proof screw-cap closure of the type initially described, which is characterized in that the inner cap possesses, on its inside, an inner chamber (which faces the container) and also possesses a cavity in its upper end face, which chamber and cavity are connected with one another by a first passage which at all times freely permits the coupling member to pass, that a second ball-circulating channel, which connects the cavity to the inner chamber, is provided for the coupling member, which channel possesses a window in the outer side wall of the inner cap, between the cavity and the chamber, and that the outer cap possesses, on its inner wall, a projecting portion with at least one niche, which portion is so arranged that, in the non-actuating position, it at least partially covers the window of the ball-circulating channel and thereby prevents passage of the coupling member through the said channel, whilst, when the outer cap is rotated so that the niche faces the window, the coupling member can pass from the cavity into the window, whilst at the same time projecting into the niche, as a result of which the aforesaid positive connection is made between the inner cap and the outer cap and both caps can be unscrewed from the mouth of the container.
Preferably, a recess is provided in the side wall of the inner cap, which recess extends below the window and is deeper than the lower edge of the niche in the inner wall of the outer cap, and the coupling member rests against the bottom face of the said recess when it projects into the niche.
It is also preferred that the region of the window in the outer side wall of the inner cap should have a step, with the reach of the circulating channel between the window and the cavity terminating above the step, and the reach of the channel between the window and the chamber terminating below the step in the side wall of the cap and being staggered relative to the orifice of the first reach of the channel, in the direction in which the closure is rotated to close it, so that the coupling member projecting into the niche of the outer cap is pushed into the orifice of the second reach of the channel on turning the outer cap in the closing direction, and thus is able to leave the niche, whereby the outer cap and the inner cap become again disengaged.
The entry passage from the second reach of the channel into the chamber can advantageously also be so designed that the coupling member is prevented from entering this reach of the channel from the chamber.
It is also advantageous to provide, between the outer cap and the inner cap, a locking device by means of which the inner cap is moved together with the outer cap when the latter is rotated in the closing direction, whilst the inner cap is released when rotating the outer cap in the opening direction.
Preferably, that marginal edge of the niche in the inner wall of the outer cap, which on rotation of the latter in the opening direction is brought into contact with the coupling member projecting into the niche, is so arranged relative to the coupling marginal edge of the window of the inner cap above the step, against which the coupling member is pressed on rotating the closure to open it, that, with the coupling member removed from the niche, the said edge of the niche does not come into engagement with the coupling marginal edge of the window. For this purpose, the annular step, adjacent to the window, in the outer wall of the inner cap can have ramps which rise in the opening direction of rotation and are of sufficient length so as to prevent, through raising the lifting faces, sliding on the ramps, of an annular shoulder in the inner wall of the outer cap, any engagement between the said niche edge and the coupling marginal edge of the window.
Preferably, the coupling member is a ball, and the sealing member is advantageously firmly connected to the inner cap, so as to seal the inner chamber, whereby the coupling member, especially the ball, is prevented from dropping out. Finally, the sealing member can possess a cavity, on its side which faces the inner chamber of the inner cap, in which the coupling member is held securely, to prevent a shift in its position, when the cap is in the normal upright position.